Type 2 diabetes mellitus and exercise impairment

Effect of Cardiac Rehabilitation on Cardiorespiratory Fitness in Patients With Acute Myocardial Infarction: Role of Diabetes Mellitus and Glycated Hemoglobin Level

PURPOSE

Following acute myocardial infarction (AMI), patients with diabetes mellitus (DM) have a poorer prognosis than those without DM. This study aimed to investigate the benefit of cardiac rehabilitation on cardiorespiratory fitness in patients with AMI, examining whether this effect varied depending on DM and glycated hemoglobin (HbA1c) levels.

METHODS

Data were collected from the medical records of 324 patients diagnosed with AMI who were subsequently referred to participate in a supervised exercise-based cardiac rehabilitation program. Cardiorespiratory fitness was assessed using cardiopulmonary exercise testing before and at 3 and 6 mo after the start of cardiac rehabilitation. Linear mixed models were used to evaluate changes in cardiorespiratory fitness between patients with and without DM during the follow-up period.

RESULTS

In total, 106 patients (33%) had DM. Both patients with and without DM showed a significant improvement in cardiorespiratory fitness from baseline to the 6-mo follow-up. However, the improvement was significantly lower in patients with DM than in those without DM (1.9 ± 1.5 vs. 3.7 ± 3.2 mL/kg/min, P < .001). Among patients with DM, those with HbA1c levels < 7% showed a greater improvement in cardiorespiratory fitness than those with HbA1c ≥ 7% (2.7 ± 1.5 vs. 1.1 ± 1.8 mL/kg/min, P < .001) during the follow-up period.

CONCLUSIONS

Improvements in cardiorespiratory fitness following cardiac rehabilitation were significantly lower in patients with AMI and DM. The response to cardiac rehabilitation in patients is influenced by HbA1c levels. These findings suggest potential implications for individualizing cardiac rehabilitation programming and ensuring optimal glycemic control in patients with AMI and DM.

The Effectiveness of Clinician-Led Community-Based Group Exercise Interventions on Health Outcomes in Adults with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis evaluated the combined effects of clinician-led and community-based group exercise interventions on a range of health outcomes in adults with type 2 diabetes mellitus. Our literature search spanned Medline, Scopus, PubMed, Embase, and CINAHL databases, focusing on peer-reviewed studies published between January 2003 and January 2023. We included studies involving participants aged 18 years and older and articles published in English, resulting in a dataset of eight studies with 938 participants. Spanning eight peer-reviewed studies with 938 participants, the analysis focused on the interventions' impact on glycemic control, physical fitness, and anthropometric and hematological measurements. Outcomes related to physical fitness, assessed through the six-minute walk test, the 30 s sit-to-stand test, and the chair sit-and-reach test, were extracted from five studies, all of which reported improvements. Anthropometric outcomes from seven studies highlighted positive changes in waist circumference and diastolic blood pressure; however, measures such as body mass index, systolic blood pressure, weight, and resting heart rate did not exhibit significant changes. Hematological outcomes, reviewed in four studies, showed significant improvements in fasting blood glucose, triglycerides, and total cholesterol, with glycemic control evidenced by reductions in HbA1c levels, yet LDL and HDL cholesterol levels remained unaffected. Ten of the fifteen outcome measures assessed showed significant enhancement, indicating that the intervention strategies implemented may offer substantial health benefits for managing key type 2 diabetes mellitus-related health parameters. These findings in combination with further research, could inform the refinement of physical activity guidelines for individuals with type 2 diabetes mellitus, advocating for supervised group exercise in community settings.

Impaired muscle oxygenation despite normal pulmonary function in type 2 diabetes without complications

Long-term hyperglycemia in individuals with type 2 diabetes (T2D) can detrimentally impact pulmonary function and muscle oxygenation. As a result, these factors can impede the body's adaptation to physical exertion. We aimed to evaluate the oxygen pathway during maximal exercise among overweight/obese individuals with type 2 diabetes free from complications, in comparison with a group of matched overweight/obese individuals without diabetes, specifically concentrating on the effects on pulmonary function and muscle oxygenation. Fifteen overweight/obese adults with type 2 diabetes [glycated hemoglobin (HbA1c) = 8.3 ± 1.2%] and 15 matched overweight/obese adults without diabetes underwent pre- and post exercise lung function assessment. A maximal incremental exercise test was conducted, monitoring muscle oxygenation using near-infrared spectroscopy and collecting arterial blood gas samples. Both groups exhibited normal lung volumes at rest and after exercise. Spirometric lung function did not significantly differ pre- and post exercise in either group. During maximal exercise, the type 2 diabetes group showed significantly lower augmentation in total hemoglobin and deoxygenated hemoglobin compared with the control group. Despite comparable usual physical activity levels and comparable heart rates at exhaustion, the type 2 diabetes group had a lower peak oxygen consumption than controls. No significant differences were found in arterial blood gas analyses ([Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text]) between the groups. Individuals with type 2 diabetes free from complications displayed normal pulmonary function at rest and post exercise. However, impaired skeletal muscle oxygenation during exercise, resulting from reduced limb blood volume and altered muscle deoxygenation, may contribute to the lower V̇o2peak observed in this population.NEW & NOTEWORTHY Individuals with type 2 diabetes free from micro- and macrovascular complications have normal resting pulmonary function, but their V̇o2peak is impaired due to poor skeletal muscle oxygenation during exercise. Tailoring exercise regimes for this population should prioritize interventions aimed at enhancing muscle oxygenation and blood flow improvement.

Effect of Exercise Training on Some Anti-Inflammatory Adipokines, High Sensitivity C-Reactive Protein, and Clinical Outcomes in Sedentary Adults With Metabolic Syndrome

OBJECTIVE

This study aimed to investigate the effects of aerobic interval training and resistance training on anti-inflammatory adipokines, high sensitivity C-reactive protein, and clinical outcomes in sedentary men with metabolic syndrome.

METHODS

A total of 33 sedentary men with metabolic syndrome (age: 46.2 ± 4.6 years; body mass index: 35.4 ± 1.9 kg.m2) were randomly assigned to one of 3 groups: aerobic interval training (n = 12), resistance training (n = 10), or control (n = 11). Participants in the exercise groups completed a 12-week training program, 3 sessions per week, while those in the control group maintained their sedentary lifestyle. The levels of high sensitivity C-reactive protein (hs-CRP), omentin-1, adiponectin, lipid profiles, blood pressure, glucose metabolism, body composition, and peak oxygen uptake (VO2peak) were measured at baseline and after the intervention.

RESULTS

Both aerobic interval training and resistance training significantly improved the levels of omentin-1 and adiponectin, as well as reduced inflammation, as indicated by a decrease in hs-CRP levels. Exercise training also led to significant improvements in lipid profiles, blood pressure, glucose metabolism, and body composition. Specifically, the aerobic interval training group had significantly greater increases in high-density lipoprotein cholesterol and VO2peak, as well as greater reductions in low-density lipoprotein cholesterol, triglycerides, and total cholesterol compared to the resistance training group.

CONCLUSION

Exercise training, particularly aerobic interval training and resistance training, can be an effective non-pharmacological intervention for managing inflammation and improving cardiovascular health in metabolic syndrome patients.

Type 2 Diabetes Related Mitochondrial Defects in Peripheral Mononucleated Blood Cells from Overweight Postmenopausal Women

Type 2 diabetes (T2D) is a multisystem disease that is the subject of many studies, but the earliest cause of the disease has yet to be elucidated. Mitochondrial impairment has been associated with diabetes in several tissues. To extend the association between T2D and mitochondrial impairment to blood cells, we investigated T2D-related changes in peripheral mononucleated blood cells’ (PBMCs) mitochondrial function in two groups of women (CTRL vs. T2D; mean age: 54.1 ± 3.8 vs. 60.9 ± 4.8; mean BMI 25.6 ± 5.2 vs. 30.0 ± 5), together with a panel of blood biomarkers, anthropometric measurements and physiological parameters (VO2max and strength tests). Dual-energy X-ray absorptiometry (DXA) scan analysis, cardio-pulmonary exercise test and blood biomarkers confirmed hallmarks of diabetes in the T2D group. Mitochondrial function assays performed with high resolution respirometry highlighted a significant reduction of mitochondrial respiration in the ADP-stimulated state (OXPHOS; −30%, p = 0.006) and maximal non-coupled respiration (ET; −30%, p = 0.004) in PBMCs samples from the T2D group. The total glutathione antioxidant pool (GSHt) was significantly reduced (−38%: p = 0.04) in plasma samples from the T2D group. The fraction of glycated hemoglobin (Hb1Ac) was positively associated with markers of inflammation (C-reactive protein-CRP r = 0.618; p = 0.006) and of dyslipidemia (triglycerides-TG r = 0.815; p < 0.0001). The same marker (Hb1Ac) was negatively associated with mitochondrial activity levels (OXPHOS r = −0.502; p = 0.034; ET r = −0.529; p = 0.024). The results obtained in overweight postmenopausal women from analysis of PBMCs mitochondrial respiration and their association with anthropometric and physiological parameters indicate that PBMC could represent a reliable model for studying T2D-related metabolic impairment and could be useful for testing the effectiveness of interventions targeting mitochondria.

[Geriatric aspects for the management of diabetes mellitus (Update 2023)]

There is a high prevalence of diabetes mellitus in the elderly population of industrial countries. The present article provides recommendations for the screening, prevention and treatment of elderly diabetic patients according to current scientific evidence.

Activity-related dyspnea in older adults participating in the Canadian Longitudinal Study on Aging

BACKGROUND

Dyspnea is associated with functional impairment and impaired quality of life. There is limited information on the potential risk factors for dyspnea in an older adult population.

OBJECTIVES

Among older adults aged 45 to 85 years of age, what sociodemographic, environmental, and disease related factors are correlated with dyspnea?

DESIGN

We used cross-sectional questionnaire data collected on 28,854 participants of the Canadian Longitudinal Study of Aging (CLSA). Multinomial regression was used to assess the independent effect of individual variables adjusting for the other variables of interest.

KEY RESULTS

The adjusted odds ratios for dyspnea "walking on flat surfaces" were highest for obesity (OR, 5.71; 95%CI, 4.71-6.93), lung disease (OR, 3.91; 95%CI, 3.41-4.49), and depression (OR, 3.68; 95%CI, 3.15-4.29), and were greater than 2 for lower income, and heart disease. The effect of diabetes remained significant after adjusting for sociodemographics, heart disease and BMI (OR, 1.61; 95%CI, 1.39-1.86). Those with both respiratory disease and depression had a 12.78-fold (95%CI, 10.09-16.19) increased odds of exertional dyspnea, while the corresponding OR for the combination of heart disease and depression was 18.31 (95%CI, 13.4-25.01).

CONCLUSIONS

In a community sample of older adults, many correlates of dyspnea exist which have significant independent and combined effects. These factors should be considered in the clinical context where dyspnea is out of proportion to the degree of heart and lung disease. Whether or not diabetes may possibly be a risk factor for dyspnea merits further investigation.

Cardiac function and exercise capacity in patients with metabolic syndrome: A cross-sectional study

Background

Metabolic syndrome is a pre-diabetes condition that is associated with increased cardiovascular morbidity and mortality. We aimed to explore how exercise capacity, cardiac structure, and function were affected in patients with metabolic syndrome.

Methods

Outpatients with echocardiography and exercise stress test combined with impedance cardiography (ETT + ICGG) results available from Nov 2018 to Oct 2020 were retrospectively enrolled. Echocardiographic, ETT + ICG profiles, and exercise performance were compared between patients with metabolic syndrome and the ones without. Sensitivity analyses were performed excluding patients without established coronary heart disease and further 1:1 paired for age and gender, respectively. Multiple linear regression was used to find out related predictors for maximal metabolic equivalents (METs).

Results

Three hundred and twenty-third patients were included, among whom 97 were diagnosed as metabolic syndrome. Compared to patients without metabolic syndrome, echocardiography showed that patients with metabolic syndrome had a significantly lower E/A ratio (p &lt; 0.001). Besides, they have larger left atrium, larger right ventricle, and thicker interventricular septum (all p &lt; 0.001), but similar left ventricular ejection fraction (P = 0.443). ICG showed that patients with metabolic syndrome had significantly higher stroke volume at rest and maximum (p &lt; 0.001), higher left cardiac work index at rest and maximum (p = 0.005), higher systemic vascular resistance (SVR) at rest (p &lt; 0.001), but similar SVI (p = 0.888). During exercise, patients with metabolic syndrome had lower maximal METs (p &lt; 0.001), and a higher proportion suffering from ST-segment depression during exercise (p = 0.009). Sensitivity analyses yielded similar results. As for the linear regression model, 6 independent variables (systolic blood pressure, BMI, E/A ratio, the height of O wave, the peak value of LCWi, and the baseline of SVR) had statistically significant effects on the maximal METs tested in exercise (R = 0.525, R2 = 0.246, P &lt; 0.001).

Conclusion

Patients with metabolic syndrome had significant structural alteration, apparent overburden of left ventricular work index, pre-and afterload, which may be the main cause of impaired exercise tolerance.

Physical performance and glycemic control under SGLT-2-inhibitors in patients with type 2 diabetes and established atherosclerotic cardiovascular diseases or high cardiovascular risk (PUSH): Design of a 4-week prospective observational study

Background

Type 2 diabetes (T2D) is associated with limitation in physical performance. Results from animal studies report enhancement of physical performance in T2D rodents treated with sodium glucose cotransporter 2 inhibitors (SGLT2is). However, in human patients with T2D and established atherosclerotic cardiovascular disease (ASCVD) or high cardiovascular risk, the impact of guideline directed SGLT2i medication on physical performance has not been sufficiently examined.

Objectives

The main objectives of this study are thus firstly, to assess the changes in physical performance after 4 weeks of exercise therapy in patients with established ASCVD or high cardiovascular risk categorized into three groups according to their glycemic control at baseline. Secondly, to investigate the association of glycemic control at baseline and new guideline directed antidiabetic treatment (inadequate glycemic control and diabetes + new SGLT2i vs. adequate glycemic control and diabetes vs. no diabetes) with change in physical performance.

Methods and design

This is a 4-week prospective observational study of 450 participants with established ASCVD or high cardiovascular risk with or without T2D and without previous SGLT2i medication undergoing exercise therapy during inpatient rehabilitation in a single center in Switzerland. Upon admission, participants are categorized into 3 groups of 150 participants each according to their glycemic control. Group I consisting of participants with inadequately controlled T2D defined as mean fasting plasma glucose (FPG) of ≥7 mmol/L, who are consequently administered new treatment with an SGLT2i. Group II comprises of participants with adequately controlled T2D with mean FPG of <7 mmol/L requiring no antidiabetic medication change. Group III consists of participants with no diabetes and mean FPG of ≤ 5.5 mmol/L. Primary outcomes are 6-min walk distance and rate of perceived exertion. Secondary outcomes are echocardiographic parameters (left ventricular mass index; global longitudinal strain average; end-diastolic volume), fatigue, muscle, metabolic, and anthropometric measures.

Ethics and dissemination

This study is conducted in accordance with the Declaration of Helsinki with ethical approval from the Cantonal Ethical Commission of Bern, Switzerland. The results will be published in a peer-reviewed journal. The implementation and reporting will be according to the SPIRIT guidelines.

Study protocol registration

https://www.clinicaltrials.gov/, identifier: NCT03422263.

Muscle Microcirculatory Responses to Incremental Exercises Are Correlated with Peak Oxygen Uptake in Individuals With and Without Type 2 Diabetes Mellitus

Background: The role of impaired oxygen extraction on peak oxygen uptake (V̇O_2peak) has been extensively studied using noninvasive and indirect methods in both diabetic patients and healthy participants. Methods: A total of 22 participants with type 2 diabetes mellitus [T2DM; median (range) age: 60 (47-70) years] and 22 controls [58 (52-69) years] with no history of diabetes were recruited (reference no. 201812135RINB). Subjects performed an exhaustive incremental exercise and were evaluated using a gas analyzer and near-infrared spectroscopy (NIRS) to determine V̇O_2peak and changes in muscle oxygenation (SmO₂) in the vastus lateralis, respectively. Measurements were taken at rest, warm-up, a period during exercise when SmO₂ reached a minimum saturation plateau, and recovery. The microcirculatory responses of the vastus lateralis muscle during incremental exercise in patients with T2DM were compared with those in control individuals, and the correlation between changes in SmO₂ and V̇O_2peak was estimated. Results: The diabetic group demonstrated lower V̇O_2peak, peak workload, peak heart rate, peak minute ventilation (all P < 0.05), and lower SmO₂ during the rest, warm-up, and recovery phases (all P < 0.05) compared with the control group. A correlation was observed between the change in SmO₂ between the warm-up and plateau value and the V̇O_2peak (r = 0.608, P = 0.006). Conclusions: The results obtained in this study using NIRS support the feasibility of directly measuring changes in muscle SmO₂ magnitudes to estimate the contributions of peripheral active muscle to systemic O₂ uptake (V̇O₂) during incremental exercise.

Canagliflozin Prevents Hyperglycemia-Associated Muscle Extracellular Matrix Accumulation and Improves the Adaptive Response to Aerobic Exercise

Chronic hyperglycemia is associated with low response to aerobic exercise training in rodent models and humans, including reduced aerobic exercise capacity and impaired oxidative remodeling in skeletal muscle. Here, we investigated whether glucose lowering with the sodium-glucose cotransporter 2 inhibitor (SGLT2i), canagliflozin (Cana; 30 mg/kg/day), could restore exercise training response in a model of hyperglycemia (low-dose streptozotocin [STZ]). Cana effectively prevented increased blood glucose in STZ-treated mice. After 6 weeks of voluntary wheel running, Cana-treated mice displayed improvements in aerobic exercise capacity, higher capillary density in striated muscle, and a more oxidative fiber-type in skeletal muscle. In contrast, these responses were blunted or absent in STZ-treated mice. Recent work implicates glucose-induced accumulation of skeletal muscle extracellular matrix (ECM) and hyperactivation of c-Jun N-terminal kinase (JNK)/SMAD2 mechanical signaling as potential mechanisms underlying poor exercise response. In line with this, muscle ECM accretion was prevented by Cana in STZ-treated mice. JNK/SMAD2 signaling with acute exercise was twofold higher in STZ compared with control but was normalized by Cana. In human participants, ECM accumulation was associated with increased JNK signaling, low VO2peak, and impaired metabolic health (oral glucose tolerance test-derived insulin sensitivity). These data demonstrate that hyperglycemia-associated impairments in exercise adaptation can be ameliorated by cotherapy with SGLT2i.

Treadmill running increases the calcium sensitivity of myofilaments in diabetic rats

The cardiovascular benefits of regular exercise are unequivocal, yet patients with type 2 diabetes respond poorly to exercise due to a reduced cardiac reserve. The contractile response of diabetic cardiomyocytes to beta-adrenergic stimulation is attenuated, which may result in altered myofilament calcium sensitivity and post-translational modifications of cardiac troponin I (cTnI). Treadmill running increases myofilament calcium sensitivity in non‑diabetic rats, and thus we hypothesized that endurance training would increase calcium sensitivity of diabetic cardiomyocytes and alter site-specific phosphorylation of cTnI. Calcium sensitivity, or pCa₅₀, was measured in Zucker Diabetic Fatty (ZDF) non-diabetic (nDM) and diabetic (DM) rat hearts after 8 weeks of either a sedentary (SED) or progressive treadmill running (TR) intervention. Skinned cardiomyocytes were connected to a capacitance-gauge transducer and a torque motor to measure force as a function of pCa (‑log[Ca²⁺]). Specific phospho-sites on cTnI and O‑GlcNAcylation were quantified by immunoblot and total protein phosphorylation by fluorescent gel staining (ProQ Diamond). The novel finding in this study was that training increased pCa₅₀ in both DM and nDM cardiomyocytes (p = 0.009). Phosphorylation of cTnI amino acid residues Ser23/24, a crucial protein kinase A site, and Threonine (Thr)144, was lower in DM hearts, but there was no effect of training on site-specific phosphorylation. Additionally, total phosphorylation and O-GlcNAcylation levels were not different between SED and TR groups. These findings suggest that regular exercise may benefit the diabetic heart by specifically targeting myofilament contractile function.

Correlates of cardiorespiratory fitness among overweight or obese individuals with type 2 diabetes

INTRODUCTION

Mechanistic studies suggest that type 2 diabetes is independently associated with low cardiorespiratory fitness (CRF). Little is known about the CRF profile in type 2 diabetes; we assessed the correlates of low CRF among overweight/obese adults with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 4215 participants with type 2 diabetes and without cardiovascular disease underwent maximal exercise testing in the Look AHEAD (Action for Health in Diabetes) study. Low CRF was defined based on the Aerobics Center Longitudinal Study reference standards. Calorie intake and physical activity were assessed using questionnaires. Body fat composition was assessed using dual-energy X-ray absorptiometry.

RESULTS

Waist circumference, systolic blood pressure, glycemic measures, whole body fat, caloric intake, and fat-free mass were inversely associated with fitness across sex (all p<0.001). Comparing with moderate or high CRF groups, the low CRF group was associated with higher adjusted odds of obesity (OR 3.19 (95% CI 1.95 to 5.20) in men, 3.86 (95% CI 2.55 to 5.84)) in women), abdominal obesity (OR 3.99 (95% CI 2.00 to 7.96) in men, 2.28 (95% CI 1.08 to 4.79) in women), hypertension (OR 1.74 (95% CI 1.09 to 2.77) in men, 1.44 (95% CI 1.02 to 2.05) in women), metabolic syndrome (OR 5.52 (95% CI 2.51 to 12.14) in men, 2.25 (95% CI 1.35 to 3.76) in women), use of beta-blocker (1.22 (95% CI 0.86 to 1.73) in men, 1.33 (95% CI 1.03 to 1.73) in women), and ACE inhibitor/angiotensin-receptor blocker (1.86 (95% CI 1.39 to 2.50) in men, 1.07 (95% CI 0.86 to 1.32) in women). Women with low CRF had higher odds of current smoking (2.02 (95% CI 1.25 to 3.28)).

CONCLUSIONS

Low CRF was associated with increased odds of cardiometabolic correlates in a large cohort of adults with type 2 diabetes.

The Application of Exercise Training for Diabetic Peripheral Neuropathy

Diabetic peripheral neuropathy (DPN) is the presence of symptoms and/or signs of peripheral nerve dysfunction in people with diabetes after the exclusion of other causes. It is associated with pain, paresthesia, sensory loss, muscle atrophy with fat infiltration, and muscular dysfunction typically starting distally in the feet and progressing proximally. Muscle deterioration within the leg and foot can lead to muscle dysfunction, reduced mobility, and increases the risk of disability, ulceration, and amputation. Exercise training is an established method for increasing the different components of physical fitness, including enhancing body composition and improving neuromuscular strength. A number of experimental studies have utilized exercise training to treat various impairments associated with DPN, such as nerve conduction velocity, pain tolerance, and balance. However, the broad spectrum of exercise training modalities implemented and differences in target outcome measurements have made it difficult to understand the efficacy of exercise training interventions or provide appropriate exercise prescription recommendations. Therefore, the aims of this review were to (1) briefly describe the pathophysiology of DPN and (2) discuss the effects of exercise training interventions on sensorimotor, metabolic, and physical functions in people with DPN.

Reexamining the Classification of Older Adults With Diabetes by Comorbidities and Exploring Relationships With Frailty, Disability, and 5-year Mortality

BACKGROUND

Limited research has been conducted to risk stratify older adults with diabetes. Our objective was to reexamine the 2005-2006 classification systems in participants who are now 5 years older.

METHODS

We examined a subsample of 884 community-residing older adults with the diagnosis of diabetes from the National Social Life, Health, and Aging Project. The primary objective was to utilize a latent class analysis (LCA) to fit a model to 11 comorbidities, comparing the 2010-2011 LCA model to that of 2005-2006. The secondary objective was to evaluate the association of the identified classes with frailty, disability, and 5-year mortality.

RESULTS

Both 2005-2006 LCA and the 2010-2011 LCA model fit 3 similar comorbidity profiles: Class 1 with the lowest rates of nearly all comorbidities, Class 2 had highest rates of obesity, hypertension, arthritis, and incontinence, and Class 3 had the higher rates of myocardial infarctions, congestive heart failure, and stroke. When compared to the healthier Class 1 (class probability = 0.67), participants with a comorbidity profile with more prevalent cardiovascular conditions (Class 3; 0.09) were at higher risk of frailty and mortality, but not disability; whereas participants with a comorbidity profile with more prevalent geriatric syndrome conditions (Class 2; 0.24) were at higher risk of frailty and disability, but not mortality.

CONCLUSIONS

We reconfirmed 3 latent classes with distinct comorbidity profiles among older adults with diabetes. However, the complex relationships between comorbidity classes with frailty, disability, and mortality will likely require revision of the current rationale for stratified goal setting and treatment selection.

Effects of water stably-enriched with oxygen as a novel method of tissue oxygenation on mitochondrial function, and as adjuvant therapy for type 2 diabetes in a randomized placebo-controlled trial

BACKGROUND

Diabetes mellitus is associated with inadequate delivery of oxygen to tissues. Cellular hypoxia is associated with mitochondrial dysfunction which increases oxidative stress and hyperglycaemia. Hyperbaric oxygenation therapy, which was shown to improve insulin sensitivity, is impractical for regular use. We evaluated the effects of water which is stably-enriched with oxygen (ELO water) to increase arterial blood oxygen levels, on mitochondrial function in the presence of normal- or high-glucose environments, and as glucose-lowering therapy in humans.

METHODS

We compared arterial blood oxygen levels in Sprague-Dawley rats after 7 days of ad libitum ELO or tap water consumption. Mitochondrial stress testing, and flow cytometry analysis of mitochondrial mass and membrane potential, were performed on human HepG2 cells cultured in four Dulbecco's Modified Eagle Medium media, made with ELO water or regular (control) water, at normal (5.5 mM) or high (25 mM) glucose concentrations. We also randomized 150 adults with type 2 diabetes (mean age 53 years, glycated haemoglobin HbA1c 8.9% [74 mmol/mol], average duration of diabetes 12 years) to drink 1.5 litres daily of bottled ELO water or drinking water.

RESULTS

ELO water raised arterial oxygen tension pO2 significantly (335 ± 26 vs. 188 ± 18 mmHg, p = 0.006) compared with tap water. In cells cultured in control water, mitochondrial mass and membrane potential were both significantly lower at 25 mM glucose compared with 5.5 mM glucose; in contrast, mitochondrial mass and membrane potential did not differ significantly at normal or high glucose concentrations in cells cultured in ELO water. The high-glucose environment induced a greater mitochondrial proton leak in cells cultured in ELO water compared to cells cultured in control medium at similar glucose concentration. In type 2 diabetic adults, HbA1c decreased significantly (p = 0.002) by 0.3 ± 0.7% (4 ± 8 mmol/mol), with ELO water after 12 weeks of treatment but was unchanged with placebo.

CONCLUSIONS

ELO water raises arterial blood oxygen levels, appears to have a protective effect on hyperglycaemia-induced reduction in mitochondrial mass and mitochondrial dysfunction, and may be effective adjuvant therapy for type 2 diabetes.

Inflammatory, antioxidant and glycemic status to different mode of high-intensity training in type 2 diabetes mellitus

BACKGROUND

Exercise has traditionally been used and prescribed as an effective and suitable way to treat type 2 diabetics Mellitus (T2DM). In this regard, we compared inflammatory, antioxidant, and glycemic status to different kinds of high-intensity interval training (strength training, HIIT, and HIIT + ST) in patients with T2DM.

METHODS AND RESULTS

Fifty-nine T2DM patients (age = 45-60 yrs) were randomly divided to strength training (ST) (n = 15), high intensity interval training (HIIT) (n = 16), HIIT + ST (n = 15) or served as control (CON) (n = 13) groups. Experimental groups performed three training sessions/week for 12 weeks. Inflammatory, antioxidant, glycemic factors, and anthropometric parameters were evaluated at baseline and after the 12 weeks of interventions. Training HIIT groups significantly improved antioxidant factors, lipid profile, and glycemic parameters (P ≤ 0.05). Interleukin 6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-α (TNF-α) significantly decreased in the three training groups. As a result of training, the overall inflammatory and antioxidant status were improved considerably in all three training groups compared to the CON group (P ≤ 0.05). In addition, there were significant differences in CRP at the follow-up values between ST and CON groups (P ≤ 0.05). Exercise time and TC were significantly improved in HIIT than in the CON group (P ≤ 0.05). The results showed a significant difference between the HIIT + ST group and the CON group in VO2_peak (P ≤ 0.05).

CONCLUSIONS

Our results showed improvement in inflammatory factors, antioxidants, and glycemic parameters in all training groups regardless of their type. However, for more benefits in T2DM patients, combination exercises can be suggested.

Community-Based Exercise and Lifestyle Program Improves Health Outcomes in Older Adults with Type 2 Diabetes

BACKGROUND

The aim of this study was to assess the efficacy of Beat It-a community-based exercise and lifestyle intervention-in improving anthropometric and physical fitness outcomes in older adults with type 2 diabetes mellitus (T2DM).

METHODS

Australians with T2DM who were aged 60 years or older were included. These individuals were enrolled in Beat It, a twice-weekly supervised group exercise and education program conducted over 8 weeks. Anthropometric measurements and physical fitness parameters were assessed at baseline and completion. Physical fitness measures were then compared to validated criterion standards of fitness levels required by older adults to remain physically independent into later life.

RESULTS

A total of 588 individuals were included in the study. At baseline, a substantial proportion of the cohort had physical fitness measures that were below the standard for healthy independent living for their gender and age. Significant improvements in waist circumference and physical fitness were observed post program and resulted in an increase in the number of participants who met the standard for healthy independent living.

CONCLUSIONS

Participation in Beat It improved important health outcomes in older adults with T2DM. A longer-term follow-up is needed to determine whether these positive changes were maintained beyond the delivery of the program.

Device-measured physical activity and its association with physical function in adults with type 2 diabetes mellitus

AIM

To quantify how differences in metrics characterizing physical activity and sedentary behaviour in type 2 diabetes are associated with physical function.

METHODS

This analysis included participants' data from the Chronotype of Patients with Type 2 Diabetes and Effect on Glycaemic Control (CODEC) cross-sectional study. Data were stratified into two groups according to their short physical performance battery (SPPB) score (impaired physical function = SPPB < 10 and normal physical function = SPPB ≥ 10). Hand-grip strength, sit-to-stand 60 (STS-60) and the Duke Activity Status Index (DASI) score were used to assess functional capacity, while physical activity metrics were measured with a wrist-worn accelerometer. The associations between physical activity metrics and measures of functional capacity were analysed using generalized linear modelling.

RESULTS

Some 635 adults (median age 66 years, 34% female) were included in this analysis. Overall, 29% of the cohort scored < 10 in the SPPB test indicating impaired physical function. This group spent more time in prolonged sedentary behaviour (600.7 vs. 572.5 min) and undertook less-intense physical activity. Each sd increase in physical activity volume and intensity gradients for those with impaired physical function was associated with 17% more repetitions for STS-60 with similar associations seen for DASI score. Each sd in sedentary time was associated with 15% fewer repetitions in STS-60 and 16% lower DASI score in those with impaired physical function, whereas in normal physical function group it was 2% and 1%, respectively.

CONCLUSIONS

The strength of the associations for physical activity measures and functional capacity were modified by physical function status, with the strongest association seen in those with impaired physical function.

Cardiorespiratory Fitness and Atherosclerotic Cardiovascular Outcomes by Levels of Baseline-Predicted Cardiovascular Risk: The Look AHEAD Study

BACKGROUND

We evaluated the associations of cardiorespiratory fitness with atherosclerotic cardiovascular disease (ASCVD) by levels of baseline-predicted ASCVD risk among adults with type 2 diabetes.

METHODS

We analyzed data from 4203 adults with type 2 diabetes in the Look AHEAD (Action for Health in Diabetes) study. Cardiorespiratory fitness was assessed using maximal exercise testing and categorized into low, moderate, and high; baseline-predicted. ASCVD risk was calculated using the American College of Cardiology/American Heart Association Pooled Cohort Equation. We used Cox regression models to estimate hazard ratios (HR) and 95% confidence intervals (CI) for ASCVD events (fatal and nonfatal myocardial infarction and stroke).

RESULTS

Over a median of 9.6 years, there were 295 ASCVD events. The effect of fitness on outcomes was different across levels of 10-year predicted ASCVD risk (P for interaction < .001). Among participants with a baseline-predicted risk of 7.5% to 20%, the HR of low (vs high) fitness group was 1.94 (95% CI, 1.12-3.35) for ASCVD events. Fitness was not significantly associated with ASCVD events in the groups with baseline-predicted risk <7.5% (HR 1.53; 95% CI, 0.49-4.76) or ≥20% (HR 1.40; 95% CI, 0.88-2.24). A similar pattern was observed for myocardial infarction and stroke separately.

CONCLUSIONS

In a large sample of type 2 diabetes individuals, the association of low fitness with incident ASCVD was modified by the baseline-predicted 10-year ASCVD risk. Our findings suggest the utility of assessing fitness in ASCVD risk stratification in type 2 diabetes, especially among those with intermediate predicted 10-year risk of ASCVD.

Microcirculatory Responses to Muscle and Tendon Exercises in Individuals With and Without Type 2 Diabetes Mellitus and the Association Between Microcirculatory and Exercise Performance

Background: This study aimed to measure and compare (1) the microcirculation and microcirculatory responses of the muscles and tendons at rest and during isometric muscle contractions in participants with and without diabetes mellitus (DM) and (2) to determine correlations between microcirculation and muscle strength. Methods: Sixty-three participants with type 2 DM and 42 physically matched controls were recruited. Baseline measurements of the microcirculation of the rectus femoris (RF) and medial gastrocnemius (MG) muscles and patellar (PT) and Achilles tendons (AT), as well as their microcirculatory changes during maximal isometric exercises, were performed and recorded by using near-infrared spectroscopy and a red laser. Data on various laboratory tests (including glycated hemoglobin, triglyceride, high-density cholesterol), the monofilament test, and the ankle-brachial index were also obtained. Results: The baseline measurements indicated that, compared with the controls, the diabetic participants had lower oxygen saturation (SpO₂) in their RF and MG muscles (both P < 0.001), and the total hemoglobin in the diabetic PT and AT was higher (P = 0.001 and P = 0.01). The minimal SpO₂ levels in the aforementioned muscles during isometric contractions were lower in the diabetes group than in the control group (P ≤ 0.001). Furthermore, there were correlations between the microcirculatory change of the RF muscle and the knee extension force. Conclusions: This study demonstrated the effects of diabetes on the microcirculation of skeletal muscles and tendons during baseline measurements and responses to maximal isometric exercises. The results support the need for preventive strategies for diabetic muscles to prevent adverse complications when performing resistance training.

Neurovascular Dysregulation During Exercise in Type 2 Diabetes

Emerging evidence suggests that type 2 diabetes (T2D) may impair the ability to properly adjust the circulation during exercise with augmented blood pressure (BP) and an attenuated contracting skeletal muscle blood flow (BF) response being reported. This review provides a brief overview of the current understanding of these altered exercise responses in T2D and the potential underlying mechanisms, with an emphasis on the sympathetic nervous system and its regulation during exercise. The research presented support augmented sympathetic activation, heightened BP, reduced skeletal muscle BF, and impairment in the ability to attenuate sympathetically mediated vasoconstriction (i.e., functional sympatholysis) as potential drivers of neurovascular dysregulation during exercise in T2D. Furthermore, emerging evidence supporting a contribution of the exercise pressor reflex and central command is discussed along with proposed future directions for studies in this important area of research.

The cardiovascular determinants of physical function in patients with end-stage kidney disease on haemodialysis

Patients with end-stage kidney disease (ESKD) are often sedentary and decreased functional capacity associates with mortality. The relationship between cardiovascular disease (CVD) and physical function has not been fully explored. Understanding the relationships between prognostically relevant measures of CVD and physical function may offer insight into how exercise interventions might target specific elements of CVD. 130 patients on haemodialysis (mean age 57 ± 15 years, 73% male, dialysis vintage 1.3 years (0.5, 3.4), recruited to the CYCLE-HD trial (ISRCTN11299707), underwent cardiovascular phenotyping with cardiac MRI (left ventricular (LV) structure and function, pulse wave velocity (PWV) and native T1 mapping) and cardiac biomarker assessment. Participants completed the incremental shuttle walk test (ISWT) and sit-to-stand 60 (STS60) as field-tests of physical function. Linear regression models identified CV determinants of physical function measures, adjusted for age, gender, BMI, diabetes, ethnicity and systolic blood pressure. Troponin I, PWV and global native T1 were univariate determinants of ISWT and STS60 performance. NT pro-BNP was a univariate determinant of ISWT performance. In multivariate models, NT pro-BNP and global native T1 were independent determinants of ISWT and STS60 performance. LV ejection fraction was an independent determinant of ISWT distance. However, age and diabetes had the strongest relationships with physical function. In conclusion, NT pro-BNP, global native T1 and LV ejection fraction were independent CV determinants of physical function. However, age and diabetes had the greatest independent influence. Targeting diabetic care may ameliorate deconditioning in these patients and a multimorbidity approach should be considered when developing exercise interventions.

Metabolomics reveals the impact of Type 2 diabetes on local muscle and vascular responses to ischemic stress

OBJECTIVE

Type 2 diabetes mellitus (T2DM) reduces exercise capacity, but the mechanisms are incompletely understood. We probed the impact of ischemic stress on skeletal muscle metabolite signatures and T2DM-related vascular dysfunction.

METHODS

we recruited 38 subjects (18 healthy, 20 T2DM), placed an antecubital intravenous catheter, and performed ipsilateral brachial artery reactivity testing. Blood samples for plasma metabolite profiling were obtained at baseline and immediately upon cuff release after 5 min of ischemia. Brachial artery diameter was measured at baseline and 1 min after cuff release.

RESULTS

as expected, flow-mediated vasodilation was attenuated in subjects with T2DM (P<0.01). We confirmed known T2DM-associated baseline differences in plasma metabolites, including homocysteine, dimethylguanidino valeric acid and β-alanine (all P<0.05). Ischemia-induced metabolite changes that differed between groups included 5-hydroxyindoleacetic acid (healthy: -27%; DM +14%), orotic acid (healthy: +5%; DM -7%), trimethylamine-N-oxide (healthy: -51%; DM +0.2%), and glyoxylic acid (healthy: +19%; DM -6%) (all P<0.05). Levels of serine, betaine, β-aminoisobutyric acid and anthranilic acid were associated with vessel diameter at baseline, but only in T2DM (all P<0.05). Metabolite responses to ischemia were significantly associated with vasodilation extent, but primarily observed in T2DM, and included enrichment in phospholipid metabolism (P<0.05).

CONCLUSIONS

our study highlights impairments in muscle and vascular signaling at rest and during ischemic stress in T2DM. While metabolites change in both healthy and T2DM subjects in response to ischemia, the relationship between muscle metabolism and vascular function is modified in T2DM, suggesting that dysregulated muscle metabolism in T2DM may have direct effects on vascular function.

Effects of physical activity on cell-to-cell communication during type 2 diabetes: A focus on miRNA signaling

Type 2 diabetes (TD2) is a progressive disease characterized by hyperglycemia that results from alteration in insulin secretion, insulin resistance, or both. A number of alterations involving different tissues and organs have been reported to the development and the progression of T2D, and more relevantly, through cell-to-cell communication pathways. Recent studies demonstrated that miRNAs are considerably implicated to cell-to-cell communication during T2D. Physical activity (PA) is associated with decreasing risks of developing T2D and acts as insulin-like factor. Cumulative evidence suggests that this effect could be mediated in part through improving insulin sensitivity in T2D and obese patients and modulating miRNAs synthesis and release in healthy patients. Therefore, the practice of PA should ideally be established before the initiation of T2D. This review describes cell-to-cell communications involved in the pathophysiology of T2D during PA.

Cardiovascular and systemic determinants of exercise capacity in people with type 2 diabetes mellitus

The global burden of heart failure (HF) is on the rise owing to an increasing incidence of lifestyle related diseases, predominantly type 2 diabetes mellitus (T2D). Diabetes is an independent risk factor for cardiovascular disease, and up to 75% of those with T2D develop HF in their lifetime. T2D leads to pathological alterations within the cardiovascular system, which can progress insidiously and asymptomatically in the absence of conventional risk factors. Reduced exercise tolerance is consistently reported, even in otherwise asymptomatic individuals with T2D, and is the first sign of a failing heart. Because aggressive modification of cardiovascular risk factors does not eliminate the risk of HF in T2D, it is likely that other factors play a role in the pathogenesis of HF. Early identification of individuals at risk of HF is advantageous, as it allows for modification of the reversible risk factors and early initiation of treatment with the aim of improving clinical outcomes. In this review, cardiac and extra-cardiac contributors to reduced exercise tolerance in people with T2D are explored.

Skeletal muscle proteins important for work capacity are altered with type 2 diabetes - Effect of 10-20-30 training

The study examined whether men with type 2 diabetes exhibit lower expression of muscle proteins important for exercise capacity, and whether exercise training promotes adaptations in these proteins. In a cross-sectional and longitudinal study, conducted at the University of Copenhagen. Twelve men with type 2 diabetes (T2D) were compared to eleven nondiabetes counterparts (ND) matched for age and body composition (body fat percentage). T2D underwent 10 weeks of high-intensity interval exercise training (10-20-30 training). T2D had lower expression of SOD1 (-62%; p < 0.001) and ETC complex V (-34%; p = 0.003), along with higher expression of ETC complex IV (+66%; p = 0.007), MFN2 (+62%; p = 0.001), and DRP1 (+30%; p = 0.028) compared to ND. T2D had higher (p < 0.001) expression of Na⁺ /K⁺ α1 (+98%), α2 (+114%), and NHE1 (+144%) than ND. In T2D, training increased exercise capacity (+9%; p < 0.001) as well as expression of SOD2 (+44%; p = 0.029), ETC complex II (+25%; p = 0.035), III (+52%; p = 0.041), IV (+23%; p = 0.005), and V (+21%; p = 0.035), CS activity (+32%; p = 0.006) as well as Na⁺ /K⁺ α1 (+24%; p = 0.034), Kir6.2 (+36%; p = 0.029), and MCT1 (+20%; p = 0.007). Men with type 2 diabetes exhibited altered expression of a multitude of skeletal muscle proteins important for exercise capacity. Ten weeks of 10-20-30 training upregulated expression of muscle proteins regulating antioxidant defense, mitochondrial function, and ion handling while enhancing exercise capacity in men with type 2 diabetes.

Prevalence of peripheral arterial disease and associated factors in people with type 2 diabetes

Abstract Introduction: The high rate of diabetes mellitus index (DM), along with the increase in cardiovascular compromise that DM favors, and the scarcity of epidemiological data regarding the prevalence of peripheral arterial disease (PAD) in this population, make it important to study risk factors associated with the development of PAD in the population with type 2 diabetes mellitus (DM2). Objective: To estimate the prevalence of PAD together with the associated factors in a sample of patients with DM2, treated in the Family Health Strategies (FHS) program, in the municipality of Pindamonhangaba, SP. Methods: Quantitative research in a cross-sectional study of 38 individuals who were diagnosed with DM2, between 40 and 77 years old, selected by convenience sampling and treated in the family health program in two different districts of the municipality. The method consisted of the evaluation of personal and anthropometric data, anamnesis and physical examination including the ankle-brachial index (ABI). Results: PAD was present in 21.1% (95%CI: 16.9 to 25.8) of the investigated population. Risk factors observed were age range of 51 to 69 years (75%), overweight (50%), systemic arterial hypertension (SAH) (100%), smoking (62.5%) and physical inactivity (87.5%). Conclusion: The prevalence of PAD was more than a fifth of those diagnosed with DM2, and the most prevalent associated risk factors were SAH, physical inactivity, smoking and overweight with and without PAD.

Greater α1-adrenergic-mediated vasoconstriction in contracting skeletal muscle of patients with type 2 diabetes

Findings presented in this article are the first to show patients with type 2 diabetes mellitus have blunted hyperemic and vasodilatory responses to dynamic handgrip exercise. Moreover, we illustrate greater α1-adrenergic-mediated vasoconstriction may contribute to our initial observations. Collectively, these data suggest patients with type 2 diabetes may have impaired functional sympatholysis, which can contribute to their reduced exercise capacity.

Type 2 diabetes is an independent predictor of lowered peak aerobic capacity in heart failure patients with non-reduced or reduced left ventricular ejection fraction

Background

Although type 2 diabetes mellitus (T2DM) is one of the most frequent comorbidities in patients with chronic heart failure (CHF), the effects of T2DM on the exercise capacity of CHF patients are fully unknown. Here, we tested the hypothesis that the coexistence of T2DM lowers CHF patients’ peak aerobic capacity.

Methods

We retrospectively analyzed the cases of 275 Japanese CHF patients with non-reduced ejection fraction (left ventricular ejection fraction [LVEF] ≥ 40%) or reduced EF (LVEF < 40%) who underwent cardiopulmonary exercise testing. We divided them into diabetic and nondiabetic groups in each CHF cohort.

Results

The mean peak oxygen uptake (VO₂) value was 16.87 mL/kg/min in the non-reduced LVEF cohort and 15.52 mL/kg/min in the reduced LVEF cohort. The peak VO₂ was lower in the diabetics versus the nondiabetics in the non-reduced LVEF cohort with the mean difference (95% confidence interval [95% CI]) of − 0.93 (− 1.82 to − 0.04) mL/kg/min and in the reduced LVEF cohort with the mean difference of − 1.05 (− 1.96 to − 0.15) mL/kg/min, after adjustment for age-squared, gender, anemia, renal function, LVEF, and log B-type natriuretic peptide (BNP). The adjusted VO₂ at anaerobic threshold (AT), a submaximal aerobic capacity, was also decreased in the diabetic patients with both non-reduced and reduced LVEFs. Intriguingly, the diabetic patients had a lower adjusted peak O₂ pulse than the nondiabetic patients in the reduced LVEF cohort, but not in the non-reduced LVEF cohort. A multivariate analysis showed that the presence of T2DM was an independent predictor of lowered peak VO₂ in CHF patients with non-reduced LVEF and those with reduced LVEF.

Conclusions

T2DM was associated with lowered peak VO₂ in CHF patients with non-reduced or reduced LVEF. The presence of T2DM has a negative impact on CHF patients’ exercise capacity, and the degree of impact is partly dependent on their LV systolic function.

SWELL1 regulates skeletal muscle cell size, intracellular signaling, adiposity and glucose metabolism

Maintenance of skeletal muscle is beneficial in obesity and Type 2 diabetes. Mechanical stimulation can regulate skeletal muscle differentiation, growth and metabolism; however, the molecular mechanosensor remains unknown. Here, we show that SWELL1 (Lrrc8a) functionally encodes a swell-activated anion channel that regulates PI3K-AKT, ERK1/2, mTOR signaling, muscle differentiation, myoblast fusion, cellular oxygen consumption, and glycolysis in skeletal muscle cells. LRRC8A over-expression in Lrrc8a KO myotubes boosts PI3K-AKT-mTOR signaling to supra-normal levels and fully rescues myotube formation. Skeletal muscle-targeted Lrrc8a KO mice have smaller myofibers, generate less force ex vivo, and exhibit reduced exercise endurance, associated with increased adiposity under basal conditions, and glucose intolerance and insulin resistance when raised on a high-fat diet, compared to wild-type (WT) mice. These results reveal that the LRRC8 complex regulates insulin-PI3K-AKT-mTOR signaling in skeletal muscle to influence skeletal muscle differentiation in vitro and skeletal myofiber size, muscle function, adiposity and systemic metabolism in vivo.

Cardiorespiratory Fitness as a Correlate of Cardiovascular, Anthropometric, and Physical Risk Factors: Using the Ruffier Test as a Template

Background

Assessment of cardiorespiratory fitness (CRF) is a standard procedure in routine clinical practices. Early identification of risk factors through screening is vital in the fight against chronic diseases. Evaluation of CRF can impose cost implications in the clinical setting; thus, a simple and easy-to-use test is to be advocated. The Ruffier test is a simple test that can assess CRF, and it is necessary to find whether the test reflects the effects of compounding factors in CRF.

Objective

This study aims to determine the association between CRF (estimated VO2max) with cardiovascular, anthropometric, and physical risk factors using the Ruffier test.

Methods

A cross-sectional study with a sample of 52 male participants was conducted. Before the Ruffier test, each participant's body weight, height, waist circumference, skinfold thickness, thigh length, lower-limb length, thigh circumference, physical activity, blood pressure, smoking, diabetes, and pulmonary functions were recorded, and these factors correlated with CRF.

Results

There was a significant inverse relationship found between the estimated VO2max and age, height, body weight, body mass index, waist circumference, a sum of skinfold, fat percentage, thigh length, lower-limb length, thigh circumference, smoking, blood pressure, heart rates, and diabetes (p < 0.05). A significant positive correlation was found between the estimated VO2max with physical activity and respiratory functions (p < 0.05). In the multivariable model, body weight and resting heart rate were significantly inversely associated with the estimated VO2max(p < 0.05).

Conclusion

Using the Ruffier test, various risk factors of CRF are correlated with the estimated VO2max. This test reflects the effects of different compounding factors on CRF; therefore, it can be used in routine clinical practices to identify the risk factors early.

Cardiovascular Determinants of Aerobic Exercise Capacity in Adults With Type 2 Diabetes

OBJECTIVE

To assess the relationship between subclinical cardiac dysfunction and aerobic exercise capacity (peak VO₂) in adults with type 2 diabetes (T2D), a group at high risk of developing heart failure.

RESEARCH DESIGN AND METHODS

Cross-sectional study. We prospectively enrolled a multiethnic cohort of asymptomatic adults with T2D and no history, signs, or symptoms of cardiovascular disease. Age-, sex-, and ethnicity-matched control subjects were recruited for comparison. Participants underwent bioanthropometric profiling, cardiopulmonary exercise testing, and cardiovascular magnetic resonance with adenosine stress perfusion imaging. Multivariable linear regression analysis was undertaken to identify independent associations between measures of cardiovascular structure and function and peak VO₂.

RESULTS

A total of 247 adults with T2D (aged 51.8 ± 11.9 years, 55% males, 37% black or south Asian ethnicity, HbA_1c 7.4 ± 1.1% [57 ± 12 mmol/mol], and duration of diabetes 61 [32-120] months) and 78 control subjects were included. Subjects with T2D had increased concentric left ventricular remodeling, reduced myocardial perfusion reserve (MPR), and markedly lower aerobic exercise capacity (peak VO₂ 18.0 ± 6.6 vs. 27.8 ± 9.0 mL/kg/min; P < 0.001) compared with control subjects. In a multivariable linear regression model containing age, sex, ethnicity, smoking status, and systolic blood pressure, only MPR (β = 0.822; P = 0.006) and left ventricular diastolic filling pressure (E/e') (β = -0.388; P = 0.001) were independently associated with peak VO₂ in subjects with T2D.

CONCLUSIONS

In a multiethnic cohort of asymptomatic people with T2D, MPR and diastolic function are key determinants of aerobic exercise capacity, independent of age, sex, ethnicity, smoking status, or blood pressure.

Near-infrared Spectroscopy of Vastus Lateralis Muscle during Incremental Cycling Exercise in patients with Type 2 Diabetes

PURPOSE

It is clinically important to elucidate the precise mechanism of exercise intolerance in patients with type 2 diabetes (T2DM). The aim of this study was to examine whether there is a difference in the time course change of the oxygenation in the vastus lateralis (VL) muscle during submaximal incremental cycling exercise between patients with T2DM and age-matched healthy subjects.

METHODS

Nine elderly men with T2DM and 10 age-matched healthy men (CON) participated in this study. All participants performed an incremental cycling exercise.Total, deoxygenated and oxygenated hemoglobin/myoglobin in the VL muscle were assessed using near-infrared spectroscopy, and cardiorespiratory response was also evaluated during the exercise.

RESULTS

There were no significant differences in the time course changes of deoxygenated hemoglobin/myoglobin between groups ( p > 0.05). However, the oxygenated hemoglobin/myoglobin in T2DM was significantly higher than that in CON at an intensity above ventilatory threshold during the incremental cycling exercise ( p< 0.05).

CONCLUSION

This study suggests that patients with T2DM had early limitation of oxygen extraction and lower capacity of oxygenated myoglobin dissociation in the VL muscle. The fact that patients with T2DM showed different oxygen kinetics in a peripheral tissue from healthy subjects may partly explain the potential mechanisms of exercise intolerance in T2DM.

Subclinical Inflammation Is Associated With Reductions in Muscle Oxygenation, Exercise Capacity and Quality of Life in Adults With Type 2 Diabetes

OBJECTIVES

Exercise capacity is related to both morbidity and mortality in patients with type 2 diabetes (T2DM). The aim of this study was to investigate the relationship between subclinical inflammation level, exercise capacity, muscle oxygenation and quality of life in T2DM.

METHODS

This study includes 28 patients with T2DM (mean age, 51.5±5.0 years; male-to-female ratio, 6:22). Exercise capacity was evaluated using an incremental symptom-limited maximal exercise test on a bicycle ergometer. Muscle oxygenation was investigated using a wearable lactate-measuring device. Diabetes-specific quality of life was assessed using the Diabetes Quality of Life Questionnaire (DQOL). Subclinical inflammation was assessed using C-reactive protein (CRP) levels.

RESULTS

CRP level was negatively correlated with peak workload during the test (r=-0.588, p=0.002), muscle oxygenation (r=-0.465, p=0.019) and the psychological impact of treatment subscale of the DQOL (r=-0.540, p=0.017), and positively correlated with body mass index (r=0.519, p=0.008), waist circumference (r=0.426, p=0.038) and fat percentage (r=0.573, p=0.004). There was no correlation between CRP and fasting blood glucose or glycated hemoglobin level (p>0.05). Peak workload was inversely related to fat percentage (r=-0.467, p=0.016) and the DQOL worry about the future impact of diabetes subscale (r=-0.501, p=0.021).

CONCLUSIONS

In our study, subclinical inflammation negatively affected muscle oxygenation, exercise capacity and quality of life independently of glycemic indicators. Our findings suggest that the degree of glycemic control is insufficient to explain lower exercise capacity. Further studies are needed to investigate subclinical inflammation-reducing interventions in T2DM.

Association between the tissue accumulation of advanced glycation end products and exercise capacity in cardiac rehabilitation patients

Background

Advanced glycation end products (AGEs) are associated with aging, diabetes mellitus (DM), and other chronic diseases. Recently, the accumulation of AGEs can be evaluated by skin autofluorescence (SAF). However, the relationship between SAF levels and exercise capacity in patients with cardiovascular disease (CVD) remains unclear. This study aimed to investigate the association between the tissue accumulation of AGEs and clinical characteristics, including exercise capacity, in patients with CVD.

Methods

We enrolled 319 consecutive CVD patients aged ≥40 years who underwent early phase II cardiac rehabilitation (CR) at our university hospital between November 2015 and September 2017. Patient background, clinical data, and the accumulation of AGEs assessed by SAF were recorded at the beginning of CR. Characteristics were compared between two patient groups divided according to the median SAF level (High SAF and Low SAF).

Results

The High SAF group was significantly older and exhibited a higher prevalence of DM than the Low SAF group. The sex ratio did not differ between the two groups. AGE levels showed significant negative correlations with peak oxygen uptake and ventilator efficiency (both P <  0.0001). Exercise capacity was significantly lower in the high SAF group than in the low SAF group, regardless of the presence or absence of DM (P <  0.05). A multivariate logistic regression analysis showed that SAF level was an independent factor associated with reduced exercise capacity (odds ratio 2.10; 95% confidence interval 1.13–4.05; P = 0.02).

Conclusion

High levels of tissue accumulated AGEs, as assessed by SAF, were significantly and independently associated with reduced exercise capacity. These data suggest that measuring the tissue accumulation of AGEs may be useful in patients who have undergone CR, irrespective of whether they have DM.

Circulatory and ventilatory power in diabetic patients: Secondary analysis of a randomized controlled trial

BACKGROUND

Circulatory (CP) and ventilatory power (VP) have been used to improve the prognostic accuracy of cardiopulmonary exercise tests in cardiovascular disease, such as coronary artery disease. However, the effects of combined resistance and aerobic exercise program on VP and CP, especially in type 2 diabetes patients, have not been adequately investigated. Thus, this new parameter can be useful to prescribe exercise programs more assertive for this population. The present study aimed to assess the effect of 3 months of combined resistance and aerobic exercise training (CET) on CP and VP in patients with type 2 diabetes.

METHODS

A randomized controlled trial was conducted involving 48 diabetic patients with an average age of 52.4 (±8.01) years old. The subjects were randomized into two groups: sedentary (SG, n = 15) and the CET group (n = 19). Cardiopulmonary exercise testing (symptom-limited incremental) was performed on a cycle ergometer, and the following parameters were measured: relative VO₂ , V_E /VCO₂ slope, linear relationship between oxygen uptake and minute ventilation, and VCO₂ . CET was performed with 30-min aerobic and 30-min resistance exercises three times a week for 12 weeks.

RESULTS

Significant (p < .05) and clinical (d ≥ .80) differences were observed that favoured CET compared with SG for the following variables: heart rate, workload, VO₂ relative peak, circulatory power peak, and VCO₂ peak. Although no statistical difference was observed for ventilatory power, there was a clinical difference (p > .05 and d ≥ 0.80) that favoured CET.

CONCLUSION

Three months of combined exercise training improved VP and CP indices in patients with type 2 diabetes when compared with a sedentary group.

Quantification of Mitochondrial Oxidative Phosphorylation in Metabolic Disease: Application to Type 2 Diabetes

Type 2 diabetes (T2D) is a growing health concern with nearly 400 million affected worldwide as of 2014. T2D presents with hyperglycemia and insulin resistance resulting in increased risk for blindness, renal failure, nerve damage, and premature death. Skeletal muscle is a major site for insulin resistance and is responsible for up to 80% of glucose uptake during euglycemic hyperglycemic clamps. Glucose uptake in skeletal muscle is driven by mitochondrial oxidative phosphorylation and for this reason mitochondrial dysfunction has been implicated in T2D. In this review we integrate mitochondrial function with physiologic function to present a broader understanding of mitochondrial functional status in T2D utilizing studies from both human and rodent models. Quantification of mitochondrial function is explained both in vitro and in vivo highlighting the use of proper controls and the complications imposed by obesity and sedentary lifestyle. This review suggests that skeletal muscle mitochondria are not necessarily dysfunctional but limited oxygen supply to working muscle creates this misperception. Finally, we propose changes in experimental design to address this question unequivocally. If mitochondrial function is not impaired it suggests that therapeutic interventions and drug development must move away from the organelle and toward the cardiovascular system.

Effects of a community-based exercise and motivational intervention on physical fitness of subjects with type 2 diabetes

BACKGROUND

This study aimed to analyze the effects of a long-term community-based combined exercise program consisting of aerobic, resistance, flexibility and agility/balance training associated with motivational interviewing on physical fitness, physiological parameters and Physical Activity (PA) levels in middle-aged and older patients with Type 2 Diabetes (T2D).

METHODS

Sixty-nine diabetic subjects (mean age 63 ± 5.2 y, 62.3% M) underwent a 9-month exercise program and 12 motivational group meetings focused on PA, while 90 diabetic controls (mean age 64 ± 6.4 y, 58% M) underwent usual PA recommendations. Changes in physical fitness measured by Senior Fitness Tests, BMI, HbA1c, waist circumference (WC) and habitual PA expressed in Metabolic Equivalent of Tasks (METs)-min/week were evaluated in each group through the International PA Questionnaire and compared between groups.

RESULTS

At the end of the intervention participants showed significant improvements in BMI (29.3 to 27.6 kg/m2, P < 0.03), HbA1c (6.5 to 6.1%, P < 0.01), WC (104.2 to 95.6 cm, P < 0.01) and all the physical fitness parameters (P < 0.01) but lower body flexibility (P = 0.82), while only upper body strength (P = 0.04) and agility (P ≤ 0.01) improved significantly in controls. Habitual PA increased in participants and controls (+67 and +19 METs-min/week, respectively, P ≤ 0.01). Changes in physical fitness and PA levels registered in the two groups differed significantly (P < 0.01), while improvements in BMI, HbA1c and WC did not (P = 0.40, P = 0.52, P = 0.05, respectively).

CONCLUSIONS

A long-term motivational exercise-based intervention may be more effective than PA recommendations only in improving physical fitness and PA levels in individuals with T2D and produce similar health improvements.

Effect of PPARγ agonist on aerobic exercise capacity in relation to body fat distribution in men with type 2 diabetes mellitus and coronary artery disease: a 1-yr randomized study

Targeting metabolic determinants of exercise performance with pharmacological agents that would mimic/potentiate the effects of exercise represents an attractive clinical alternative to counterbalance the poor exercise capacity in patients with type 2 diabetes mellitus (T2DM). We examined the effect of 1-yr treatment with the insulin sensitizer peroxisome proliferator-activated receptor (PPAR)γ agonist rosiglitazone on aerobic exercise capacity and body fat composition/distribution in men with T2DM and stable coronary artery disease (CAD). One-hundred four men (age: 64 ± 7 yr; body mass index: 30.0 ± 4.4 kg/m²) with T2DM and CAD were randomized to receive rosiglitazone or placebo for 1 yr. Aerobic exercise capacity (exercise duration) was assessed with a maximal treadmill test, and body composition/distribution were assessed by dual-energy X-ray absorptiometry/computed tomography scans. At 1 yr, patients with T2DM under PPARγ agonist treatment showed a reduction in aerobic exercise capacity compared with the control group (exercise duration change, -31 ± 8 versus 7 ± 11 s, P = 0.009). Significant increases in body fat mass (3.1 ± 0.4 kg, 12%), abdominal and mid-thigh subcutaneous adipose tissue (AT) levels, and mid-thigh skeletal muscle fat were found (all P < 0.01), whereas no effect on visceral AT levels was observed (P > 0.05) under treatment. Subcutaneous fat mass gained under PPARγ agonist was the strongest predictor of the worsening in aerobic exercise capacity (P > 0.0001); no association was found with skeletal muscle fat infiltration nor visceral AT. Treatment with the insulin sensitizer PPARγ agonist rosiglitazone in patients with T2DM and CAD is associated with a worsening in aerobic exercise capacity, which seems to be mainly attributable to weight gain and subcutaneous fat mass expansion.

Sildenafil enhances central hemodynamic responses to exercise, but not V̇o2peak, in people with diabetes mellitus

Exercise capacity is frequently reduced in people with diabetes mellitus (DM), and the contribution of pulmonary microvascular dysfunction remains undefined. We hypothesized that pulmonary microvascular disease, measured by a novel exercise echocardiography technique termed pulmonary transit of agitated contrast (PTAC), would be greater in subjects with DM and that the use of pulmonary vasodilator agent sildenafil would improve exercise performance by reducing right ventricular afterload. Forty subjects with DM and 20 matched controls performed cardiopulmonary exercise testing and semisupine exercise echocardiography 1 h after placebo or sildenafil ingestion in a double-blind randomized crossover design. The primary efficacy end point was exercise capacity (V̇o2peak) while secondary measures included pulmonary vascular resistance, cardiac output, and change in PTAC. DM subjects were aged 44 ± 13 yr, 73% male, with 16 ± 10 yr DM history. Sildenafil caused marginal improvements in echocardiographic measures of biventricular systolic function in DM subjects. Exercise-induced increases in pulmonary artery systolic pressure and pulmonary vascular resistance were attenuated with sildenafil, while heart rate (+2.4 ±1.2 beats/min, P = 0.04) and cardiac output (+322 ± 21 ml, P = 0.03) improved. However, the degree of PTAC did not change (P = 0.93) and V̇o2peak did not increase following sildenafil as compared with placebo (V̇o2peak: 31.8 ± 9.7 vs. 32.1 ± 9.5 ml·min-1·kg-1, P = 0.42). We conclude that sildenafil administration causes modest acute improvements in central hemodynamics but does not improve exercise capacity. This may be due to the mismatch in action of sildenafil on the pulmonary arteries rather than the distal pulmonary microvasculature and potential adverse effects on peripheral oxygen extraction. NEW & NOTEWORTHY This is one of the largest and most comprehensive studies of cardiopulmonary exercise performance in people with diabetes mellitus and to our knowledge the first to assess the effect of sildenafil using detailed echocardiographic measures during incremental exercise. Sildenafil attenuated the rise in pulmonary vascular resistance while augmenting cardiac output and intriguingly heart rate, without conferring any improvement in exercise capacity. The enhanced central hemodynamic indexes may have been offset by reduced peripheral O2 extraction.

Factors associated with glycemic control in community-dwelling elderly individuals with type 2 diabetes mellitus in Zhejiang, China: a cross-sectional study

BACKGROUND

Although exercise seems to be beneficial for type 2 diabetes mellitus (T2DM) patients, there is limited research elucidating the optimal accessible indices of adiposity and insulin resistance for identifying elderly T2DM patients with poor glycemic control, which could be improved by performing regular exercise.

METHODS

A community-based, cross-sectional study was conducted with 918 Chinese elderly individuals with T2DM in Zhejiang. Relevant risk factors for poor glycemic control, as determined using glycated haemoglobin A1c (HbA1c) > 7%, were explored using logistic regression analyses and included body mass index (BMI), waist circumference (WC), waist to height ratio (WHtR), fasting blood glucose (FBG), triglycerides (TGs), total cholesterol (TC), the product of fasting triglycerides and glucose (TyG), visceral adiposity index (VAI), lipid accumulation product (LAP), TyG-BMI, and TyG-WC. Comparisons of the risk factors' ability to discriminate poor glycemic control as well as their optimal cutoff values were determined using receiver operating characteristic (ROC) analyses, and then the extent of poor glycemic control risk reduction through regular exercise was examined using multivariate logistic regression analyses.

RESULTS

The overall poor glycemic control rate was 49.3%. The factors associated with poor glycemic control included FBG > 3.869, TyG > 8.73, TyG-BMI > 222.45, and TyG-WC > 713.48 in logistic regression analyses. The optimal cutoff points of FBG, TyG, TyG-WC, and TyG-BMI in discriminating poor glycemic control were 7.38, 9.22, 813.33, and 227.77, and their corresponding areas under the ROC curves were 0.864(0.840-0.886), 0.684(0.653-0.714), 0.604(0.571-0.635), and 0.574(0.541-0.606), respectively. Occasional and regular exercise reduced the odds ratios (95% confidence interval) of poor glycemic control to 0.187 (0.063-0.557) and 0.183 (0.059-0.571) for subjects with TyG-WC > 813.33 (p = 0.008), to 0.349 (0.156-0.782) and 0.284 (0.123-0.652) for subjects with TyG > 9.22 (p = 0.011), and to 0.390 (0.175-0.869) and 0.300(0.130-0.688) for subjects with TyG-BMI > 227.77 (p = 0.017), respectively, after adjusting for multiple confounding factors.

CONCLUSION

Among elderly individuals with T2DM, poor glycemic control risk might be identified using indices calculated from FBG, TG, BMI, and WC measurements, which are indicative of adiposity and insulin resistance. TyG-WC seems to be an accessible and useful indicator to identify which elderly T2DM patients would benefit from performing regular exercise to achieve good glycemic control.

Can an Exercise-Based Educational and Motivational Intervention be Durably Effective in Changing Compliance to Physical Activity and Anthropometric Risk in People with Type 2 Diabetes? A Follow-Up Study

AIMS

A nine-month motivational exercise-based intervention was previously offered to subjects with type 2 diabetes (T2D). A year after the end of the intervention, compliance to physical activity (PA) and anthropometric indices of participants were analyzed to evaluate the durability of its effects.

METHODS

PA levels, expressed as total energy expenditure per week, were assessed with the International Physical Activity Questionnaire (IPAQ). Changes in Body Mass Index (BMI), A Body Shape Index (ABSI), Hip Index (HI) z-scores, the relative mortality risk related to each of these measures, and a combined Anthropometric Risk Index (ARI) were also evaluated.

RESULTS

Of a total of the 52 subjects examined (67.9% males, mean age 61.8 ± 6.0), 46 (88.4%) were still sufficiently active as defined by IPAQ thresholds at follow-up. PA levels, anthropometric indices and related risks improved at follow-up in respect to the baseline and to the end of the intervention, although only PA levels, BMI and related measures, and ARI risk changed significantly. Habitual PA increased significantly after the intervention (p < 0.01) and this increase correlated with changes in BMI z-scores (r = -0.29, p = 0.04). BMI risk was significantly lower (p < 0.01) in participants still active at follow-up.

CONCLUSIONS

This study testifies to the persistence of compliance to PA and health benefits of a combined exercise-based and motivational intervention in subjects with T2D.

Adiposity predicts low cardiorespiratory fitness in individuals with metabolic diseases

Cardiorespiratory fitness (CRF) is impaired in those with metabolic diseases and strongly predicts mortality. We found that adiposity, not glycaemic control or disease type, is the strongest predictor of low CRF in those with metabolic diseases. We discuss how adiposity and metabolic health may relate to outcomes in obesity.

Pregnancy and post-partum muscle and cerebral oxygenation during intermittent exercise in gestational diabetes: A pilot study

OBJECTIVE

This pilot, prospective, observational, cohort study aimed to examine, for the first time, the in vivo alterations in the oxygenation of the forearm skeletal muscles and the prefrontal lobes during intermittent exercise in women diagnosed with gestational diabetes mellitus (GDM), during and after pregnancy.

STUDY DESIGN

Nine pregnant women, diagnosed with GDM, performed a 3-min intermittent handgrip exercise protocol (at 35% of Maximal Voluntary Contraction) during pregnancy (mean 27th gestational week) and following labor (mean 71 weeks). During the protocol, muscle and cerebral oxygenation were assessed with near-infrared spectroscopy. Resting vascular parameters [carotid intima-media thickness (cIMT) and hemodynamic parameters (using rheocardiography)], and hematological/biochemical parameters during pregnancy and after delivery have been compared.

RESULTS

Although changes were observed in certain hematological parameters (p< 0.05), cIMT and hemodynamic parameters were not altered post-partum. In addition, both muscle and cerebral oxygenation parameters during handgrip were not significantly altered post-partum.

CONCLUSIONS

Despite significant changes in specific hematological parameters in women with GDM, impairments in muscle and cerebral oxygenation during exercise remained at one year after labor. These results indicate that alterations in vascular parameters and muscle/cerebral oxygenation associated with GDM do not entirely reverse post-partum. Future studies are needed to examine which interventions will lead to improvements in microvascular parameters and prevent type 2 diabetes.